Paper shredders have been increasingly gaining popularity. Among components of a paper-shredding mechanism of a typical paper shredder, the motor and conveying roller provided with a cutter thereon are particularly important components. Comparatively, corresponding control circuits and enclosure are simple in construction. Improvements to paper shredders are extremely limited due to their long time existence in the marketplaces. Many manufacturers have been continuously developing their new products to stand in the market. However, improvements are relatively confined due to the very simple structure of known paper shredders. Accordingly, it is inevitable for these manufacturers to lower the price of the shredders in order to gain the profits from the marketplace.
To reduce costs, manufacturers have made efforts to improve shredding capability of the shredders on one hand; and on the other hand, they adopt inexpensive components. For example, costs will be reduced if plastic enclosure other than a metal enclosure is used to encase the rest of the components of the shredder. Enhancement of shredding performance is typically realized by improving performance of the motor. In doing so however, power consumption of the motor is also increased. According to Joule's Law, it will also cause a dramatic increase of the heat generated by the paper shredder. In particular, the shredders (mainly the motors) currently used in offices, for example, where a high quantity of paper is shredded, the shredders often halt due to overheating, thus decreasing the shredding efficiency. Even for offices where the paper-shredding requirement is low, heat accumulation inside the shredder will make plastic components such as the enclosure and circuit boards melt down eventually. Moreover, electric characteristics of certain electronic elements will also be damaged, and consequently, the lifespan of the shredder will be shortened.
The applicant has recognized that the drawbacks described above have been ignored by persons of ordinary skill in the art. Furthermore, it has not yet been observed that a cooling technique may be applied to shredders.